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The fabrication of heterojunctions is an intriguing approach to boost the reactivity of catalysts. However, facile preparation of desirable heterojunction materials remains a challenge. Here, novel CoPS3/CoS2 heterojunctions are created by an intuitive phosphatization process on the basis of structurally flexible cobalt sulfide precursors. Significant stress effect exists at these heterogeneous interfaces, resulting in lattice distortions and the exposure of more active sites. The interface interaction also modifies the catalyst's electronic structure to improve its electrical conductivity and hydrogen adsorption capabilities. Notably, the overpotential of the CoPS3/CoS2 heterojunction for electrocatalytic hydrogen evolution reaction is just 36.3 mV, which is far superior to those of single‐component catalysts and competitive with comparable catalysts reported. This work not only offers an innovative electrocatalyst but also a strategy that can be used to create heterojunctions based on related transition metal thiophosphates. [ABSTRACT FROM AUTHOR]

Despite the fact that d‐band center theory links the d electron structure of transition metals to their catalytic activity, it is yet unknown how the synergistic effect of multi‐d electrons impacts catalytic performance. Herein, novel LaNi1‐xCoxRu intermetallics containing 5d, 4d, and 3d electrons were prepared. In these compounds, the 5d orbital of La transfers electrons to the 4d orbital of Ru, which provides adsorption sites for H*. The 3d orbitals of Ni and Co interact with the 5d and 4d orbitals to generate an anisotropic electron distribution, which facilitates the adsorption and desorption of OH*. The synergistic effect of multi‐d electrons ensures efficient catalytic activity. The optimized LaNi0.5Co0.5Ru has an overpotential of 43mV at 10 mA cm−2 for alkaline electrocatalytic hydrogen evolution reaction. Beyond offering a variety of new electrocatalysts, this work reveals the multi‐d electron synergy in promoting catalytic reaction. [ABSTRACT FROM AUTHOR]

The hydrogen spillover effect has garnered considerable attention as a promising avenue to enhance the activity of the hydrogen evolution reaction (HER) in metal‐support compound materials. Herein, Pt atom dimers on the NiOOH support are successfully synthesized with a reversed hydrogen spillover effect, demonstrating much better alkaline HER activity than Pt single atoms and Pt clusters. Atomic and electronic structure characterizations unequivocally verify the anchoring of Pt atom dimers on NiOOH through Pt─O bonds, thus obtaining a reversed and enhanced hydrogen spillover effect. Theoretical and experimental results indicate that NiOOH exhibits pronounced water dissociation capability, while the Pt atom dimers, in comparison to Pt single atoms and Pt clusters, demonstrate superior hydrogen desorption ability. The reversed spillover with Pt atom dimers leads to remarkable HER activity in alkaline solutions, as evidenced by an ultra‐small overpotential of 13 mV at 10 mA cm−2. These findings not only provide insights into the potential use of atom dimers for HER, but also shed light on reversed spillover in designing high‐performance catalysts. [ABSTRACT FROM AUTHOR]

Molybdenum diselenide and cobalt diselenide have been commonly implemented in electrocatalytic hydrogen evolution reaction (HER). However, there have been few research on the creation of their three‐phase heterojunctions and the associated HER process. Herein, we constructed a three‐phase heterostructure sample consisting of orthorhombic CoSe2, cubic CoSe2 and MoSe2 and we investigated its HER performance. The sample shows microsphere morphology composed of nanosheets with interfacial interactions between the components. It possesses an overpotential of −136 mV at −10 mA cm−2 in acid medium, which is superior to that of single component and most two‐phase heterostructures. Especially, the overpotential at −200 mA cm−2 is smaller than that of Pt/C. The excellent performance can be attributed to the d‐orbital upshift of the Co active sites due to charge redistribution between the three‐phase heterojunction and the optimization of the hydrogen free energy. This work provides inspiration for exploring the application of other multi‐component heterojunctions in electrocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

The construction of heterostructures is a versatile tactic to enhance catalytic activity. However, it is still elusive to realize the modulation of the interlayer spacing in this way to further improve the performance. Here, strong interfacial coupling between CoSe2 and MoSe2 by constructing CoSe2/MoSe2 heterostructures is achieved. The interlayer spacing of MoSe2 is compressed by 0.3 Å. The enhanced charge transfer is validated by X‐ray absorption spectroscopy and X‐ray photoelectron spectroscopy. Coupled with the morphology of hollow microtubes, which can facilitate the exposure of active sites, CoSe2/MoSe2 heterostructures reported here exhibit high activity (119 mV at 10 mA cm−2) and excellent stability with small degradation after 50 h operation, surpassing other analogous powdered electrocatalysts. This work sheds light on the importance of tuning the interlayer spacing to improve electrocatalytic activity. [ABSTRACT FROM AUTHOR]

The discovery and identification of novel active sites are paramount for deepening the understanding of the catalytic mechanism and driving the development of remarkable electrocatalysts. Here, we reveal that the genuine active sites for the hydrogen evolution reaction (HER) in LaRuSi are Si sites, not the usually assumed Ru sites. Ru in LaRuSi has a peculiar negative valence state, which leads to strong hydrogen binding to Ru sites. Surprisingly, the Si sites have a Gibbs free energy of hydrogen adsorption that is near zero (0.063 eV). The moderate adsorption of hydrogen on Si sites during the HER process is also validated by in situ Raman analysis. Based on it, LaRuSi exhibits an overpotential of 72 mV at 10 mA cm−2 in alkaline media, which is close to the benchmark of Pt/C. This work sheds light on the recognition of real active sites and the exploration of innovative silicide HER electrocatalysts. [ABSTRACT FROM AUTHOR]

Alloying noble metals with non‐noble metals is a promising method to fabricate catalysts, with the advantages of reduced noble metal usage and excellent activity. In this work, electron‐abundant Ir/Rh sites, as highly active centers for the hydrogen evolution reaction (HER), are realized by fabricating Ir1−xRhxSb alloys through the arc‐melting method. The electron transfer from Sb to Ir/Rh makes the latter negatively charged, leading to considerably optimized adsorption for active H species during HER. As a result, the Ir1−xRhxSb alloy exhibits outstanding activity for HER, with an optimized overpotential of 22 mV at 10 mA cm–2 and a Tafel slope of 47.6 mV dec–1. This work provides insights into highly active alloys and sheds light on the utilization of electron‐abundant metal atoms. [ABSTRACT FROM AUTHOR]

The separate modulation of the adsorption of *O and *OOH is challenging in oxygen evolution reaction (OER), which results in a large overpotential and slow kinetics. To balance the adsorption of the two active species, here, a way to regulate the local spin state and band structure simultaneously in Ni3S2 nanosheets is reported. The adequate doping of W heteroatoms causes the electron depletion from the Ni active site, which modulates the spin state of eg electrons, weakening the adsorption of *O. Additionally, the introduction of S vacancies contributes to the upshift of the d band center, which strengthens the adsorption of *OOH. In this manner, the adsorption of Ni3S2 for the active intermediates is optimized, resulting in a considerably improved overpotential of 246 mV at 100 mA cm−2 and a Tafel slope of 66 mV dec−1. This work provides insights into the exploration of OER catalysts through synergistic modulation of the spin state and the band structure. [ABSTRACT FROM AUTHOR]

The coordination environment is crucial for the activity of an electrocatalyst, which defines the interaction between the central and adjacent atoms. In traditional 2D MX2 (M = Mo, W, etc., X = S, Se), M is usually coordinated with 6 X atoms in either trigonal prismatic (2H) or octahedral (1T) polyhedrons. With such a coordination configuration, only the edge X sites exhibit activity for hydrogen evolution reaction (HER). Here, a planar‐coordination transition metal chalcogenide, PdSe2 is reported, as an efficient electrocatalyst for the HER in an alkaline electrolyte. By reducing the spatial polyhedron coordination to planar polygon coordination, the M sites in PdSe2 can be efficiently activated to interact with the adsorptive intermediates. As a result, both Pd and Se atoms act as active sites for hydrogen evolution with neutral adsorption ability. With an overpotential of 138 mV at 10 mA cm−2, this work advances the exploration of planar‐coordination HER electrocatalysts. [ABSTRACT FROM AUTHOR]

Optimizing the hydrogen adsorption Gibbs free energy (ΔGH) of active sites is essential to improve the overpotential of the electrocatalytic hydrogen evolution reaction (HER). We doped graphene‐like Co0.85Se with sulfur and found that the active sites are reversed (from cationic Co sites to anionic S sites), which contributed to an enhancement in electrocatalytic HER performance. The optimal S‐doped Co0.85Se composite has an overpotential of 108 mV (at 10 mA cm−2) and a Tafel slope of 59 mV dec−1, which exceeds other reported Co0.85Se‐based electrocatalysts. The doped S sites have much higher activity than the Co sites, with a hydrogen adsorption Gibbs free energy (ΔGH) close to zero (0.067 eV), which reduces the reaction barrier for hydrogen production. This work provides inspiration for optimizing the intrinsic HER activity of other related transition metal chalcogenides. [ABSTRACT FROM AUTHOR]

Significant efforts have been dedicated to boosting the electrocatalytic activity of Co9S8 for the oxygen evolution reaction (OER); however, with limited improvement in its intrinsic activity, which relies on careful band engineering. Fe possesses one less 3d electron and lower electronegativity than Co, suggesting a higher d‐band center when forming polyhedron with S anions. Here, to improve the intrinsic activity by elevating the d‐band center, the six‐coordinated octahedrons in Co9S8 are redesigned utilizing an Fe‐incorporated topochemical deintercalation method. Through substituting partial Co octahedrons by Fe octahedrons with higher d‐band, the overall d‐band center is regulated to achieve optimized adsorption and thus superior OER activity. With a reduction of 95 mV on the overpotential (at 10 mA cm−2), this work sheds lights on the design of OER catalysts through polyhedron engineering using topochemical deintercalation. [ABSTRACT FROM AUTHOR]

Photocatalysis is an effective technique to remove antibiotic residues from aquatic environments. Typical metal sulfides like Zn3In2S6 have been applied to a wide range of photocatalytic applications. However, there are currently no readily accessible methods to increase its antibiotic‐degrading activity. Here, a facile hydrothermal approach is developed for the preparation of flower‐like Zn3In2S6 with tunable sulfur lattice defects. Photogenerated carriers can be separated and transferred more easily when there is an adequate amount of lattice defects. Moreover, lattice defect‐induced electronic modulation enhances light utilization and adsorption properties. The modified Zn3In2S6 demonstrates outstanding photocatalytic degradation activity for levofloxacin, ofloxacin, and tetracycline. This work sheds light on exploring metal sulfides with sulfur lattice defects for enhancing photocatalytic activity. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To assess the value of Fourier-transform infrared (FT-IR) spectroscopic analysis in detecting colorectal carcinoma. METHODS: Fifty pairs of specimens of exfoliated cells from patients with colorectal carcinoma, who had undergone colorectal resection, were analyzed by using FT-IR spectrometry. Exfoliated cells were obtained by scraping off: (i) the foci of the colorectal carcinoma; and (ii) the normal mucosa more than 5 cm away from the foci. Cell specimens were fixed and smeared onto two slides: a gold-coated slide for the infrared spectrometry and a conventional one for histopathological evaluation. The spectra from 28 pairs of specimens were analyzed by logistic regression with multiple factors to establish a statistical model for predicting the probability of colorectal cancers, and then the spectra of the remaining 22 pairs were judged according to the model. Their corresponding diagnostic accuracy was calculated. RESULTS: Substantial differences were found in the spectral properties of cancer and non-cancer cells, which were evident in the frequency region of 1000–1350/cm. A shift of the phosphodiester groups of nucleic acids was noted: compared with the spectral features of non-cancerous cells, the distance between VsPO2– and VasPO2– was shorter in cancerous cells. The C–O stretching bonds of cell proteins were significantly changed in the frequency region of 1140–1180/cm. In non-cancerous cells, the peak intensity of 1155/cm was stronger than that of 1174/cm, whereas in cancerous cells the peak intensity of 1155/cm was weaker than that of 1174/cm; the peak intensity ratio of 1174/cm: 1155/cm was increased in cancerous cells. The spectral characteristics of the spectrometric data from the 22 pairs of specimens were consistent with those of the base-model data. The other 22 pairs of specimens were analyzed according to the model, indicating that Fourier-transform... [ABSTRACT FROM AUTHOR]

Cobalt phosphosulphide (CoPS) has recently been recognized as a potentially effective electrocatalyst for the hydrogen evolution reaction (HER). However, there have been no research on the design of CoPS‐based heterojunctions to boost their HER performance. Herein, CoPS/Co4S3 heterojunction was prepared by phosphating treatment based on defect‐rich flower‐like Co1‐xS precursors. The high specific surface area of nanopetals, together with the heterojunction structure with inhomogeneous strain, exposes more active sites in the catalyst. The electronic structure of the catalyst is reconfigured as a result of the interfacial interactions, which promote the catalyst‘s ability to adsorb hydrogen and conduct electricity. The synergistic effect of the Co and S dual‐site further enhance the catalytic activity. The catalyst has overpotentials of 61 and 70 mV to attain a current density of 10 mA cm−2 in acidic and alkaline media, respectively, which renders it competitive with previously reported analogous catalysts. This work proposes an effective technique for constructing transition metal phosphosulfide heterojunctions, as well as the development of an efficient HER electrocatalyst. [ABSTRACT FROM AUTHOR]

The surface reconstruction of electrochemically activated catalysts is an effective way to improve performance. However, there is currently a dearth of study on the surface reconstruction of silicide catalysts for hydrogen evolution reactions (HER). Here, a new HER electrocatalyst, LaRuSi3, is synthesized and electrochemically triggered it to produce Ru clusters on its surface. Experimental data and theoretical simulations reveal that Ru clusters optimize the charge distribution of LaRuSi3, which promotes the adsorption of water by Ru sites and improves the adsorption of hydrogen by Si sites. The conductivity and electrochemical active sites of the catalysts are also enhanced. The catalyst has an overpotential of 45 mV to attain a current density of 10 mA cm−2 in alkaline media, which exceeds the majority of other Ru‐based compounds. This work contributes to the exploration of more efficient novel silicides HER electrocatalysts and broadens the application of surface reconstruction techniques. [ABSTRACT FROM AUTHOR]